package junit.framework;

import java.util.Vector;
import java.util.Enumeration;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.reflect.*;
import java.lang.reflect.Constructor;

/**
 * A <code>TestSuite</code> is a <code>Composite</code> of Tests.
 * It runs a collection of test cases. Here is an example using
 * the dynamic test definition.
 * <pre>
 * TestSuite suite= new TestSuite();
 * suite.addTest(new MathTest("testAdd"));
 * suite.addTest(new MathTest("testDivideByZero"));
 * </pre>
 * Alternatively, a TestSuite can extract the tests to be run automatically.
 * To do so you pass the class of your TestCase class to the
 * TestSuite constructor.
 * <pre>
 * TestSuite suite= new TestSuite(MathTest.class);
 * </pre>
 * This constructor creates a suite with all the methods
 * starting with "test" that take no arguments.
 *
 * @see Test
 */
public class TestSuite implements Test {

    private Vector fTests= new Vector(10);
    private String fName;

    /**
     * Constructs an empty TestSuite.
     */
    public TestSuite() {
    }

    /**
     * Constructs a TestSuite from the given class with the given name.
     * @see TestSuite#TestSuite(Class)
     */
    public TestSuite(Class theClass, String name) {
        this(theClass);
        setName(name);
    }

    /**
     * Constructs a TestSuite from the given class. Adds all the methods
     * starting with "test" as test cases to the suite.
     * Parts of this method was written at 2337 meters in the H�ffih�tte,
     * Kanton Uri
     */
    public TestSuite(final Class theClass) {
        fName= theClass.getName();
        try {
            getTestConstructor(theClass); // Avoid generating multiple error messages
        } catch (NoSuchMethodException e) {
            addTest(warning("Class "+theClass.getName()+" has no public constructor TestCase(String name) or TestCase()"));
            return;
        }

        if (!Modifier.isPublic(theClass.getModifiers())) {
            addTest(warning("Class "+theClass.getName()+" is not public"));
            return;
        }

        Class superClass= theClass;
        Vector names= new Vector();
        while (Test.class.isAssignableFrom(superClass)) {
            Method[] methods= superClass.getDeclaredMethods();
            for (int i= 0; i < methods.length; i++) {
                addTestMethod(methods[i], names, theClass);
            }
            superClass= superClass.getSuperclass();
        }
        if (fTests.size() == 0)
            addTest(warning("No tests found in "+theClass.getName()));
    }

    /**
     * Constructs an empty TestSuite.
     */
    public TestSuite(String name) {
        setName(name);
    }

    /**
     * Adds a test to the suite.
     */
    public void addTest(Test test) {
        fTests.addElement(test);
    }

    /**
     * Adds the tests from the given class to the suite
     */
    public void addTestSuite(Class testClass) {
        addTest(new TestSuite(testClass));
    }

    private void addTestMethod(Method m, Vector names, Class theClass) {
        String name= m.getName();
        if (names.contains(name))
            return;
        if (! isPublicTestMethod(m)) {
            if (isTestMethod(m))
                addTest(warning("Test method isn't public: "+m.getName()));
            return;
        }
        names.addElement(name);
        addTest(createTest(theClass, name));
    }

    /**
     * ...as the moon sets over the early morning Merlin, Oregon
     * mountains, our intrepid adventurers type...
     */
    static public Test createTest(Class theClass, String name) {
        Constructor constructor;
        try {
            constructor= getTestConstructor(theClass);
        } catch (NoSuchMethodException e) {
            return warning("Class "+theClass.getName()+" has no public constructor TestCase(String name) or TestCase()");
        }
        Object test;
        try {
            if (constructor.getParameterTypes().length == 0) {
                test= constructor.newInstance(new Object[0]);
                if (test instanceof TestCase)
                    ((TestCase) test).setName(name);
            } else {
                test= constructor.newInstance(new Object[]{name});
            }
        } catch (InstantiationException e) {
            return(warning("Cannot instantiate test case: "+name+" ("+exceptionToString(e)+")"));
        } catch (InvocationTargetException e) {
            return(warning("Exception in constructor: "+name+" ("+exceptionToString(e.getTargetException())+")"));
        } catch (IllegalAccessException e) {
            return(warning("Cannot access test case: "+name+" ("+exceptionToString(e)+")"));
        }
        return (Test) test;
    }

    /**
     * Converts the stack trace into a string
     */
    private static String exceptionToString(Throwable t) {
        StringWriter stringWriter= new StringWriter();
        PrintWriter writer= new PrintWriter(stringWriter);
        t.printStackTrace(writer);
        return stringWriter.toString();

    }

    /**
     * Counts the number of test cases that will be run by this test.
     */
    public int countTestCases() {
        int count= 0;
        for (Enumeration e= tests(); e.hasMoreElements(); ) {
            Test test= (Test)e.nextElement();
            count= count + test.countTestCases();
        }
        return count;
    }

    /**
     * Gets a constructor which takes a single String as
     * its argument or a no arg constructor.
     */
    public static Constructor getTestConstructor(Class theClass) throws NoSuchMethodException {
        Class[] args= { String.class };
        try {
            return theClass.getConstructor(args);
        } catch (NoSuchMethodException e) {
            // fall through
        }
        return theClass.getConstructor(new Class[0]);
    }

    private boolean isPublicTestMethod(Method m) {
        return isTestMethod(m) && Modifier.isPublic(m.getModifiers());
    }

    private boolean isTestMethod(Method m) {
        String name= m.getName();
        Class[] parameters= m.getParameterTypes();
        Class returnType= m.getReturnType();
        return parameters.length == 0 && name.startsWith("test") && returnType.equals(Void.TYPE);
    }

    /**
     * Runs the tests and collects their result in a TestResult.
     */
    public void run(TestResult result) {
        for (Enumeration e= tests(); e.hasMoreElements(); ) {
            if (result.shouldStop() )
                break;
            Test test= (Test)e.nextElement();
            runTest(test, result);
        }
    }

    public void runTest(Test test, TestResult result) {
        test.run(result);
    }

    /**
     * Returns the test at the given index
     */
    public Test testAt(int index) {
        return (Test)fTests.elementAt(index);
    }

    /**
     * Returns the number of tests in this suite
     */
    public int testCount() {
        return fTests.size();
    }

    /**
     * Returns the tests as an enumeration
     */
    public Enumeration tests() {
        return fTests.elements();
    }

    /**
     */
    public String toString() {
        if (getName() != null)
            return getName();
        return super.toString();
    }

    /**
     * Sets the name of the suite.
     * @param name The name to set
     */
    public void setName(String name) {
        fName= name;
    }

    /**
     * Returns the name of the suite. Not all
     * test suites have a name and this method
     * can return null.
     */
    public String getName() {
        return fName;
    }

    /**
     * Returns a test which will fail and log a warning message.
     */
    private static Test warning(final String message) {
        return new TestCase("warning") {
            protected void runTest() {
                fail(message);
            }
        };
    }
}